The president seldom exercised his power as commander in chief until we got nukes. Each president has set his own policy in this regard. Some exercised more power and some less.

While it wasn't taught this way in my history classes, it's pretty well established now through his diaries and other documents that Truman was lied to by his generals when Hiroshima and Nagasaki were bombed. First, he was told that the nuke could be used tactically against military bases and when he found that an entire city was leveled he was horrified. Then, his generals opted to go after Nagasaki without consulting him. Finally, he dug his feet in before a third city was destroyed. He put a lot of checks in place against a runaway military that Eisenhower then mostly removed.

In lieu of controls against a runaway military, Eisenhower bowed to pressure against the Korean War by establishing the "use of force authorization" which actually undermined the president's ability to control his generals. The generals could act independently, but if he personally ordered that troops go in the president would first need congressional authorization.

So, it was easier for a president to let his spy agencies and military act without direct orders for interventions and this led directly to the toxic chaotic mess of unlawful invasions, assassination and botched intelligence operations that many of us remember from the 1970s and 1980s.

So, a president who is too dull to read or understand an intelligence-briefing and who cedes his military authority to his generals is perfectly in line with the authority of the office. And we know from history what it will likely lead to.

Military planners lay out the best possible scenarios of an operation to their leaders. No one ever seems to ask what happens if.... They always seem to ignore the possibility that the enemy just might, you know, fight back.

After all it isn't their fault if something goes wrong, it just goes up the chain of command to the President, who takes the fall

“No persons are more frequently wrong, than those who will not admit they are wrong.”
-- François de La Rochefoucauld

QuoteOnamuji
Truman was lied to by his generals when Hiroshima and Nagasaki were bombed.

I wouldn't call that an accurate reading of history.

Truman found himself in an unexpectedly complex high-stakes game with new ever-changing rules, as Stalin's promises on Eastern Europe dissolved, and with no clear line of communication to whoever was in charge in Japan. Truman placed too much trust in incoming Secretary of State Jimmy Byrnes, who thought he should have been FDR's VP and now in the Oval Office. Byrne saw the bomb as the trump card that could help control Stalin, and Truman didn't seek the opinions of Allied military leaders, who were nearly all opposed to its use.

I highly recommend Gar Alperovitz's book The Decision to Use the Atomic Bomb.